Receptacle cage, receptacle assembly, and transceiver module assembly

ABSTRACT

In a receptacle cage, a front EMI finger in a tubular shape serving as a first shield member is provided on the entire periphery of a substantially rectangular module slot. In addition, a gap between the peripheral edge of a slot of a cover, into which a plug connector for the optical module connected to a receptacle connector in a receptacle connector accommodating portion is inserted, and a peripheral surface of a plug connector and a gap between a lower surface of the cover and a surface, on which a printed wiring board is mounted, are shielded by an EMI gasket serving as a second shield member and an EMI gasket serving as a third shield member, respectively.

CROSS-REFERENCE TO THE RELATED APPLICATIONS

This application is a continuation-in-part of application Ser. No.14/223,140 filed on Mar. 24, 2014, which is a continuation ofapplication Ser. No. 13/595,422 filed on Aug. 27, 2012, which claims thebenefit of Japanese Patent Application No. 2011-188604 filed Aug. 31,2011. The disclosures of the prior applications are hereby incorporatedby reference herein in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a receptacle cage, a receptacleassembly, and a transceiver module assembly.

2. Description of the Related Art

In an optical communication system, a transceiver module has been putinto practical use in order to transmit an optical signal transmittedthrough an optical connector and the like to a mother board. Asdisclosed in Japanese Patent Laid-Open No. 2005-520296, for example,such a transceiver module is located on a chassis which constitutes acommunication system. The transceiver module comprises the followingconstituents as main elements, namely, an optical module (which isreferred to as a module assembly in Japanese Patent Laid-Open No.2005-520296), and an optical module receptacle (which is referred to asa receptacle assembly in Japanese Patent Laid-Open No. 2005-520296)mounted on a circuit board serving as a mother board and configured todetachably accommodate the optical module.

An optical cable connector and an optical cable for establishinginterconnection with another system, for example, are connected to aport at an end portion of the optical module exposed to a front cover ofthe chassis. When the optical module is connected to the optical modulereceptacle, a portion being connected of the optical module is connectedto a connected portion of a receptacle connector mounted on a portion ofthe circuit board inside the optical module receptacle. The portionbeing connected of the receptacle connector is electrically connected tothe above-mentioned circuit board. Hereby, the optical cable connectorand the optical cable are electrically connected to the circuit boardvia the transceiver module.

Moreover, as disclosed in Japanese Patent Laid-Open No. 2005-520296, alooped EMI gasket collar and resilient metal spring gaskets are providedas a countermeasure for radio wave interference (electromagneticinterference, or EMI) in the periphery of a module insertion slot of theoptical module receptacle in the transceiver module. In addition,multiple EMI gaskets are provided respectively on a front edge as wellas two side edges of a lower opening, which is formed in the vicinity ofthe receptacle connector inside the optical module receptacle. Herewith,an EMI shield is formed at a junction between the receptacle connectorand the optical module.

Further, as also disclosed in Japanese Patent Laid-Open No. 2005-520296,a measure for heat dissipation has been proposed that a heat sink may beprovided on an upper surface of the optical module receptacle in thetransceiver module.

In the above-described countermeasure for the radio wave interference,unnecessary radiation of noise from the inside of the transceiver modulelocated in the chassis to the inside of the chassis is harmful to otherelectronic components on the circuit board as well. Accordingly, it isalso required to inhibit such noise radiation into the chassis through agap between an outer peripheral portion of the optical module and aninner peripheral portion of the optical module receptacle.

Japanese Patent Laid-Open No. 2005-520296 discloses a proposal of theconfiguration in which the multiple EMI gaskets are providedrespectively on the front edge as well as the two side edges of thelower opening formed in the vicinity of the receptacle connector in theoptical module receptacle.

However, a gap is formed between an upper surface portion at the outerperipheral portion of the optical module in the optical modulereceptacle and the inner peripheral portion of the optical modulereceptacle opposed to the upper surface portion. In particular, a givenamount of a relative play in a direction of attaching or detaching theoptical module is provided between the optical module and the opticalmodule receptacle. Accordingly, it is not easy to tightly seal the gapbetween the outer peripheral portion of the optical module and the innerperipheral portion of the optical module receptacle. In short, theabove-described configuration proposed in Japanese Patent Laid-Open No.2005-520296 is likely to cause noise radiation through the gap and istherefore insufficient in light of the countermeasure for the radio waveinterference.

SUMMARY OF THE INVENTION

In view of the above-described problem, the present invention aims toprovide a receptacle cage, a receptacle assembly, and a transceivermodule assembly. The receptacle cage, a receptacle assembly, and atransceiver module assembly can reliably suppress noise radiation fromthe inside to the outside of the receptacle cage.

A receptacle cage used in a receptacle assembly to be mounted on awiring board in a housing of a communication system according to thepresent invention, comprises: a module accommodating portion made of ametal and configured to detachably accommodate an optical module, themodule accommodating portion having a module slot provided at one end toallow passage of the optical module, and a bottom wall portion coming incontact with a lower surface of the optical module; a connectoraccommodating portion made of a metal, the connector accommodatingportion communicating with the module accommodating portion and having aconnector cover made of a metal and configured to shield a connector towhich the optical module is connected; a first shield member provided onan entire periphery of the module slot and configured to come intocontact with the optical module and to shield electromagnetic noisegenerated in the module accommodating portion so as to avoid radiationof the noise into the housing; a second shield member provided in aregion corresponding to a boundary portion between the connectoraccommodating portion and the module accommodating portion and at theperiphery of a slot for the connector cover for the connectoraccommodating portion, and configured to come into contact with theoptical module and to shield the electromagnetic noise generated in theconnector accommodating portion; and third shield members provided inregions being different from a region where the second shield member isprovided, and between the connector accommodating portion and the wiringboard, the third shield members configured to shield the electromagneticnoise generated in the connector accommodating portion.

A receptacle assembly to be mounted on a wiring board in a housing of acommunication system according to the present invention, comprises: aconnector connected to an optical module; a receptacle cage made of ametal and including: a module accommodating portion made of a metal andconfigured to detachably accommodate the optical module, the moduleaccommodating portion having a module slot provided at one end to allowpassage of the optical module, and a bottom wall portion coming incontact with a lower surface of the optical module; a connectoraccommodating portion made of a metal, the connector accommodatingportion communicating with the module accommodating portion and having aconnector cover made of a metal and configured to shield a connector towhich the optical module is connected; a first shield member provided onan entire periphery of the module slot and configured to come intocontact with an outer peripheral surface of the optical module and toshield electromagnetic noise generated in the module accommodatingportion so as to avoid radiation of the noise into the housing; a secondshield member made of a metal, the second shield member provided at theperiphery of a slot for the connector cover at the connectoraccommodating portion, and configured to come into contact with theoptical module and to shield the electromagnetic noise generated in theconnector accommodating portion; and third shield members provided inregions being different from a region where the second shield member isprovided and between the connector accommodating portion and the wiringboard, the third shield members configured to shield the electromagneticnoise generated in the connector accommodating portion; wherein a nibformed at the periphery of the connector cover is engaged with a holeformed at a closed end of the connector accommodating portion.

A receptacle assembly to be mounted on a wiring board in a housing of acommunication system according to the present invention, comprises: aconnector connected to an optical module; a receptacle cage made of ametal and including: a module accommodating portion made of a metal andconfigured to detachably accommodate the optical module, the moduleaccommodating portion having a module slot provided at one end to allowpassage of the optical module, and a bottom wall portion coming incontact with a lower surface of the optical module; a connectoraccommodating portion made of a metal, the connector accommodatingportion communicating with the module accommodating portion and having aconnector cover made of a metal and configured to shield a connector towhich the optical module is connected; a first shield member provided onan entire periphery of the module slot and configured to come intocontact with an outer peripheral surface of the optical module and toshield electromagnetic noise generated in the module accommodatingportion so as to avoid radiation of the noise into the housing; a secondshield member made of a metal, the second shield member provided at theperiphery of a slot for the connector cover at the connectoraccommodating portion, and configured to come into contact with theoptical module and to shield the electromagnetic noise generated in theconnector accommodating portion; and third shield members provided inregions being different from a region where the second shield member isprovided and between the connector accommodating portion and the wiringboard, the third shield members configured to shield the electromagneticnoise generated in the connector accommodating portion; a heat sinkconfigured to dissipate heat generated in the optical module; and a heatsink holder configured to detachably fix the heat sink with respect to aposition right above the module accommodating portion and the connectoraccommodating portion in the receptacle cage, wherein a stopper piece ofthe heat sink holder is fixed to a fixing piece of the connector coverprotruding outside through a hole formed at the receptacle cage.

A transceiver module assembly to be mounted on a wiring board in ahousing of a communication system according to the present invention,comprises: an optical module having a plug connector; a connectorconnected to the plug connector of the optical module; and an opticalmodule receptacle assembly including: a module accommodating portionconfigured to detachably accommodate the optical module, the moduleaccommodating portion having a module slot provided at one end to allowpassage of the optical module; a connector accommodating portion made ofa metal, the connector accommodating portion communicating with themodule accommodating portion and accommodating the connector; aconnector cover provided on the connector accommodating portion andconfigured to cover the connector; a first shield member made of ametal, the first shield member provided on an entire periphery of themodule slot and configured to come into contact with an outer peripheralsurface of the optical module and to shield electromagnetic noisegenerated in the module accommodating portion so as to avoid radiationof the electromagnetic noise into the housing; a second shield memberprovided at a base end of the plug connector of the optical module, andconfigured to come into contact with the connector cover and to shieldthe electromagnetic noise generated in the connector accommodatingportion; and third shield members provided in regions being differentfrom a region where the first shield member is provided and between theconnector accommodating portion and the wiring board, the third shieldmembers configured to shield the electromagnetic noise generated in theconnector accommodating portion.

With the receptacle cage, receptacle assembly, and transceiver moduleassembly according to the present invention, there are provided thefirst shield member provided on the entire periphery of the module slotand configured to come into contact with the optical module and toshield the electromagnetic noise generated in the module accommodatingportion so as to avoid the radiation of the noise into the housing; thesecond shield member provided in the region corresponding to theboundary portion between the connector accommodating portion and themodule accommodating portion and at the periphery of the slot for theconnector cover for the connector accommodating portion, and configuredto come into contact with the optical module and to shield theelectromagnetic noise generated in the connector accommodating portion;and the third shield members provided in the regions being differentfrom the region where the second shield member is provided, and betweenthe connector accommodating portion and the wiring board, the thirdshield members configured to shield the electromagnetic noise generatedin the connector accommodating portion. Thus, the radiation of the noisefrom the inside of the receptacle for the optical module to the outsidethereof can be suppressed with certainly.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view showing an example of areceptacle assembly according to the present invention;

FIG. 2 is a perspective view schematically showing external appearanceof a case which mounts an example of a transceiver module assemblyaccording to the present invention;

FIG. 3 is a perspective view illustrating an internal configuration ofthe housing in the example shown in FIG. 2;

FIG. 4A is a perspective view showing an example of a receptacle cageaccording to the present invention;

FIG. 4B is a perspective view illustrating a partial enlarged portion ofthe example shown in FIG. 4A;

FIG. 4C is a perspective view illustrating a state of insertion of aplug connector of an optical module in the example shown in FIG. 4B;

FIG. 5 is a perspective view showing external appearance of the opticalmodule;

FIG. 6A is a perspective view illustrating a partial enlarged portion ofthe optical module shown in FIG. 5 in a state where a lower plate isdetached therefrom;

FIG. 6B is a perspective view illustrating a partially broken awayportion of the optical module shown in FIG. 6A;

FIG. 6C is a partial cross-sectional view of a portion of the opticalmodule shown in FIG. 6B;

FIG. 7 is an enlarged perspective view illustrating a receptacleconnector used in the example of the receptacle assembly shown in FIG.1;

FIG. 8 is a cross-sectional view taken along the VIII-VIII line in FIG.7;

FIG. 9A is a perspective view illustrating a contact terminal used inthe receptacle connector shown in FIG. 7;

FIG. 9B is a perspective view illustrating another contact terminal usedin the receptacle connector shown in FIG. 7;

FIG. 10 is a cross-sectional view made available for explanation of anoperation of the transceiver module assembly shown in FIG. 2;

FIG. 11 is a partial enlarged perspective view of the transceiver moduleassembly shown in FIG. 2;

FIG. 12 is a cross-sectional view taken along the XII-XII line in FIG.11;

FIG. 13A is a cross-sectional view made available for explanation of anoperation of the transceiver module assembly shown in FIG. 2;

FIG. 13B is a cross-sectional view used for explanation of an operationof the transceiver module assembly shown in FIG. 2;

FIG. 14 is a cross-sectional view made available for explanation ofupside-down insertion of the optical module into the transceiver moduleassembly shown in FIG. 2;

FIG. 15 is a side view of the example shown in FIG. 14;

FIG. 16 is a perspective view illustrating a state where a heat sink ismounted on an upper part of the optical module receptacle assembly shownin FIG. 1;

FIG. 17 is a perspective view showing another example of the receptacleassembly according to the present invention as well as a heat sink;

FIG. 18 is a perspective view showing a heat sink holder used in theexample shown in FIG. 17;

FIG. 19 is a partial cross-sectional view of a main part of the exampleshown in FIG. 17; and

FIG. 20 is an enlarged perspective view of a main part of anotherexample of an optical module.

DESCRIPTION OF THE EMBODIMENTS

FIG. 2 shows an example of a transceiver module assembly according tothe present invention together with a housing 18 for embedding theassembly.

An end portion of an optical module 14 of a transceiver module assembly10 to be described later protrudes out of an operating side end surface18F of the housing 18. An optical connector, to which one end of anoptical cable FC is connected, is connected to a port provided at theend portion of the optical module 14. Another end of the optical cableFC is connected to an optical connector of another housing whichconstitutes an unillustrated communication system.

As shown in FIG. 3, the housing 18 configured to define an enclosedspace inside contains a printed wiring board 16 on which the transceivermodule assembly 10 is mounted. In FIG. 3, one transceiver moduleassembly 10 is mounted on one printed wiring board 16. However, thepresent invention is not limited only to this configuration and multipletransceiver module assemblies 10 may be mounted on one printed wiringboard 16.

An opening 18 a is formed on the operating side end surface 18F of thehousing 18. A front EMI fingers 12FF, which is made of a metal andprovided at an end portion on a module slot side of the a receptaclecage 12 to be described later, is inserted into the opening 18 a.

The transceiver module assembly 10 includes the optical module 14 and anoptical module receptacle assembly.

As shown in FIG. 5, the optical module 14 includes the followingconstituents as main elements, namely, an upper case 14A and a lowerplate 14B being made of a metal and constituting a profile portion, anda module board 14S to be located at a predetermined position in ahousing space defined between the upper case 14A and the lower plate14B.

A protection wall 14 a in a thin plate shape is formed on one endportion of the upper case 14A in such a manner as to be continuous withan upper surface of the upper case 14A and to protrude in a longitudinaldirection. The protection wall 14 a and a protection wall 14 b to bedescribed later are intended to protect a plug connector 14P to bedescribed later in the event that the optical module 14 is dropped bymistake. A latch mechanism is provided at another end portion of theupper case 14A. The latch mechanism includes a release plate and a latchlever. When the latch lever is rotatably moved in a direction indicatedwith an arrow R in FIG. 5, i.e., counterclockwise, to a virtual planeshared with a lower surface of the lower plate 14B, a fixing piece of arelease plate moves in the direction indicated with an arrow to bedetached from a locking piece 12LF to be described later and the fixingpiece of a release plate is set to an unlocked state. In addition, whenthe latch lever is rotatably moved in a direction opposite to thedirection indicated with the arrow R in FIG. 5, the fixing piece of therelease plate is fixed on the locking piece 12LF of a receptacle cage 12to be described later. Herewith, the optical module 14 is set to alocked state with respect to the receptacle cage 12.

As enlarged in FIG. 6A, an electrode portion 14E which constitutes theplug connector 14P is provided on one end portion of the module board14S. Contact pads are arranged parallel to one another at givenintervals on a common plane on each of front and back surfaces of theelectrode portion 14E. As shown in FIG. 6A, a pair of nibs 14N arerespectively formed near both side surfaces of the electrode portion 14Eof the module board 14S. Each nib 14N is fixed on a peripheral edge of agroove on a board support wall 14AF of the upper case 14A. As shown inFIG. 6C, the module board 14S is inserted to the grooves such that theelectrode portion 14E of the module board 14S is set substantiallyparallel to the protection wall 14 a. As enlarged in FIG. 6B and FIG.6C, leaf springs 14LS are provided in such a manner as to face therespective nibs 14N while interposing the board support wall 14AFtherebetween. The pair of nibs 14N are securely fixed on the boardsupport wall 14AF because of pressing the board support wall 14AF by therespective leaf springs 14LS. Thus, a play between the module board 14Sand the upper case 14A is eliminated. As a consequence, a projectionlength from an end surface of the board support wall 14AF to a tip ofthe plug connector 14P is accurately controlled.

As shown in FIG. 5, the protection wall 14 b in a thin plate shape isformed on one end portion of the lower plate 14B in such a manner as tobe continuous with a lower surface of the lower plate 14B and toprotrude in the longitudinal direction. As shown in FIG. 6C, theprotection wall 14 b is formed substantially parallel to the plugconnector 14P and the protection wall 14 a while defining givenintervals respectively therewith. As shown in FIG. 15, a projectionlength La of the protection wall 14 a is set slightly greater than aprojection length Lb of the protection wall 14 b and a projection lengthof the plug connector 14P.

As shown in FIG. 1, the optical module receptacle assembly includes thefollowing constituents as main elements, namely, the receptacle cage 12placed on the printed wiring board 16 and configured to detachablyaccommodate the above-described optical module 14, a receptacleconnector 22 accommodated in a receptacle connector accommodatingportion 12D of the receptacle cage 12, and a connector cover 20 coveringthe receptacle connector 22.

As shown in FIG. 1, for example, the receptacle cage 12 is formed bypressing a thin plate of stainless steel or phosphor bronze, or morepreferably stainless steel having good thermal conductivity. Thereceptacle cage 12 is provided with a module accommodating portion 12Aand the receptacle connector accommodating portion 12D therein.

The module accommodating portion 12A is defined by side walls 12RW and12LW which face each other at a given interval, and by a bottom wallportion 12BP of the accommodating portion 12A. The side walls 12RW and12LW extend in an X-coordinate axis direction in terms of a Cartesiancoordinate system illustrated in FIG. 1, i.e., in a direction of matingand unmating the optical module 14. Each of the side walls 12RW and 12LWhas the locking piece 12LF placed in the vicinity of a module slot to bedescribed later. Each locking piece 12LF is selectively engaged with thefixing piece of the release plate of the optical module 14 describedabove so as to establish the locked state of the above-described opticalmodule 14 with respect to the module accommodating portion 12A.

The module accommodating portion 12A has a module slot which is open inthe X-coordinate axis direction at one end of the module accommodatingportion. Herewith, the optical module 14 is mounted and demountedthrough the module slot. The tubular front EMI fingers 12FF serving as afirst shield member is provided on the entire periphery of the moduleslot which has a substantially rectangular cross section. An innerperipheral portion of the front EMI fingers 12FF comes into contact withan outer peripheral portion of the optical module 14 to be inserted tothe fingers 12FF. In addition, an outer peripheral portion of the frontEMI fingers 12FF comes into contact with a peripheral edge of theopening 18 a of the housing 18, for example. Hereby, when the receptaclecage 12 is press-fitted into the opening 18 a of the housing 18 as shownin FIG. 3, a gap between the opening 18 a of the housing 18 and theouter peripheral portion of the receptacle cage 12 is shielded by thefront EMI fingers 12FF made of a metal. As a consequence, noise isconfined in the housing 18, and there is no risk of leakage of the noiseto the outside through the gap between the outer peripheral portion ofthe optical module 14 and the inner peripheral portion of the moduleaccommodating portion 12A.

In addition, another end of the module accommodating portion 12A opposedto the module slot communicates with the inside of the receptacleconnector accommodating portion 12D via a guide plate portion 20PW (seeFIG. 4A) of the connector cover 20. As shown in FIG. 1, a substantiallyrectangular opening 12 b that is open along a Z coordinate axis isformed at a portion opposed to the bottom wall portion 12BP. A pair ofhooks 12 ta configured to selectively hold a pair of fixing pieces (seeFIG. 16) of a heat sink holder 32 to be described later are integrallyformed with the receptacle cage 12 on a peripheral edge of the opening12 b. The pair of hooks 12 ta are formed in a line in a Y-coordinateaxis direction at a given interval corresponding to the interval of thepair of fixing pieces described above.

As shown in FIG. 4A, both end portions on short sides of the bottom wallportion 12BP connecting lower ends of the side walls 12RW and 12LW arein contact with a surface of the printed wiring board 16. In addition,as enlarged in FIG. 12, one of the end portions on the short sides ofthe bottom wall portion 12BP is provided with a bend piece 12BPT. Thebend piece 12BPT bent downward from the bottom wall portion 12BP comesinto contact with a side of a looped ground contact pad 16CPG (seeFIG. 1) formed on the surface of the printed wiring board 16. Herewith,the receptacle cage 12 is connected to ground. In addition, a portion ofthe wall surface portion 12BP excluding the above-mentioned end portionon the short side is provided with a given clearance (an air layer) CLDbetween the portion and the surface of the printed wiring board 16 bymeans of the bend piece 12BPT as shown in FIG. 12. Hereby, when the airinside the housing 18 flows through the clearance CLD with theassistance of a fan or the like, the bottom wall portion 12BP is cooleddown by the air layer whereby heat generated in the optical module 14 isefficiently dissipated through the receptacle cage 12. Moreover, inlight of the printed wiring board 16, the conductive pattern on thesurface can also be formed at a region on the printed wiring board 16located below a region of the bottom wall portion 12BP except theabove-mentioned end portion on the short side of the bottom wall portion12BP. As a consequence, design freedom of the conductive pattern is alsoincreased.

As shown in FIG. 4A, press-fitting nibs 12Pi (i=1 to n, n is a positiveinteger) are formed at given intervals on both long sides of the bottomwall portion 12BP. As shown in FIG. 1, the press-fitting nibs 12Pi arerespectively press-fitted into pores 16 ai (i=1 to n, n is the positiveinteger) formed on the surface of the printed wiring board 16corresponding to the array of the press-fitting nibs 12Pi. Hereby, alower end surface of the receptacle cage 12 is cohered and fixed to thesurface of the printed wiring board 16. In this case, as partiallyenlarged in FIG. 4B and FIG. 4C, lower end surfaces 12EM1, 12EM2, 12EM3,and 12EM4 on a portion forming the receptacle connector accommodatingportion 12D in the receptacle cage 12 are cohered to the above-describedground contact pad 16CPG, thereby giving an EMI shield.

As enlarged in FIG. 4A, the receptacle connector accommodating portion12D, which is open toward the surface of the printed wiring board 16, isdefined by a receptacle connector-side closed end portion facing themodule slot of the receptacle cage 12, an upper surface defining aperipheral edge of the opening 12 b on the receptacle connector side,and receptacle connector-side portions of the side walls 12RW and 12LW.

As shown in FIG. 1 and FIG. 11, a top EMI fingers 12TF made of a metaland serving as a second shield member is provided at a portionconstituting an upper surface of the receptacle connector accommodatingportion 12D. When the plug connector 14P of the optical module 14 isconnected to the receptacle connector 22, the top EMI fingers 12TF isconfigured to come into contact with an outer peripheral surface of theprotection wall 14 a of the optical module 14 as enlarged in FIG. 12. Inaddition, as shown in FIG. 11, a pair of nibs 12N for holding theconnector cover 20 to be described later are formed in positions closerto the receptacle connector-side closed end portion than the top EMIfingers 12TF.

Side EMI fingers 12SRF and 12SLF made of a metal and serving as thirdshield members are also provided respectively in positions on the sidewalls 12RW and 12LW facing the guide plate 20PW of the connector cover20, namely, regions corresponding to a boundary portion between thereceptacle connector accommodating portion 12D and the moduleaccommodating portion 12A, for example. As shown in FIG. 1, the side EMIfingers 12SRF and 12SLF respectively straddle the receptacle connectoraccommodating portion 12D and the module accommodating portion 12A andextend in the longitudinal direction in such a manner to face eachother. Accordingly, a position of one end portion of each side EMIfingers 12SRF or 12SLF is positioned closer to the module slot than theposition of an end portion of the top EMI fingers 12TF.

In addition, when the plug connector 14P of the optical module 14 isconnected to the receptacle connector 22, the side EMI fingers 12SRF and12SLF respectively come into contact with side surfaces of the uppercase 14A and the lower plate 14B of the optical module 14 which areopposed thereto as shown in FIG. 4C and FIG. 11.

Hereby, a gap between an inner peripheral surface of the receptacle cage12 and outer peripheral surfaces of the upper case 14A and the lowerplate 14B of the optical module 14 is shielded by the top EMI fingers12TF as well as the side EMI fingers 12SRF and 12SLF and the lower plate14B comes into contact with the bottom wall portion 12BP. Therefore, thegenerated noise is confined in the receptacle cage 12, and there is norisk of radiation of the noise to the housing 18 through the gap betweenthe optical module 14 and the receptacle connector accommodating portion12D.

As enlarged in FIG. 4B, a pair of hook members 12 tb to be fixed with apair of fixing pieces of the heat sink holder to be described later areformed integrally with the receptacle cage 12 at the receptacleconnector side-closed end portion. An opening 12 a is formed on aperipheral edge of each of the hook members 12 tb.

The connector cover 20 is made of a metal material, for example. Asshown in FIG. 1, the connector cover 20 includes the guide plate 20PWconfigured to guide the plug connector 14P of the optical module 14 whenthe optical module 14 is mounted and demounted, and a shield portion 20A(see FIG. 10) configured to accommodate the receptacle connector 22inside and to cover the receptacle connector 22 while defining apredetermined clearance.

As shown in FIG. 4B, the guide plate 20PW includes a slot 20PWc intowhich the plug connector 14P of the optical module 14 is inserted, and acutaway portion 20PWa into which the protection wall 14 b of the opticalmodule 14 is inserted. The slot 20PWc and the cutaway portion 20PWa arepartitioned by a partition wall 20PWb. The guide plate 20PW isintegrally formed with the connector cover 20 in such a manner as tointersect an upper surface portion (shield portion 20A) of the connectoraccommodating portion.

An upper surface portion of the shield portion 20A of the connectorcover 20 is provided with a step portion 20R, which is configured toguide the protection wall 14 a of the optical module 14 as shown in FIG.10 and FIG. 12 upon mating and demating of the optical module 14.Herewith, when the optical module 14 is inserted upside down into thereceptacle cage 12 by mistake as shown in FIG. 14 and FIG. 15, the tipof the protection wall 14 a touches an end surface of the guide plate20PW of the connector cover 20. Therefore, erroneous insertion of theoptical module 14 is prevented. At that time, the tip of the protectionwall 14 a touches the end surface of the guide plate 20PW of theconnector cover 20 whereas the tip of the plug connector 14P does nottouch the end surface of the guide plate 20PW. Therefore, the tip of theplug connector 14P is prevented from breakage in case of erroneousinsertion of the optical module 14.

In addition, holes 20 d into which the pair of nibs 12N of thereceptacle cage 12 are press-fitted are formed near the step portion 20Rof the connector cover 20 (see FIG. 11).

As shown in FIG. 7 and FIG. 8, the receptacle connector 22 includes aconnector insulator provided with a slot 22A which allows detachableinsertion of the plug connector 14P of the optical module 14, andmultiple contact terminals 26 ai and 28 ai (i=1 to n, n is a positiveinteger).

The connector terminals 26 ai and 28 ai are configured to connectelectrodes on the plug connector 14P of the optical connector 14electrically to a group of electrodes 16CPA (see FIG. 1) which areconnected to the conductive pattern on the printed wiring board 16. Asshown in FIG. 9B, each contact terminal 26 ai comprises a movablecontact point portion 26M in which a contact point 26 ma to come intocontact with an electrode 14E on the plug connector 14P of the opticalconnector 14 is provided on one end, and a connection portion 26B inwhich a fixation terminal portion 26 fa to be soldered to one of thegroup of electrodes 16CPA is provided on one end. The connection portion26B is formed integrally with and perpendicularly to the other end ofthe movable contact point portion 26M. As shown in FIG. 9A, each contactterminal 28 ai comprises a movable contact point portion 28M in which acontact point 28 ma to come into contact with an electrode portion 14Eon the plug connector 14P of the optical connector 14 is provided on oneend, a fixation portion 28F in which a fixation terminal portion 28 fato be soldered to one of the group of electrodes 16CPA is provided onone end, and a connection portion 28B to connect the other end of themovable contact point portion 28M to the other end of the fixationportion 28F. The connection portion 28B is provided with a nib to bepress-fitted and fixed to a wall portion which forms a slot 22B of theconnector insulator.

As shown in FIG. 8, the connector insulator is molded by using a resinmaterial. The connector insulator has the slot 22A where mounting anddemounting of the plug connector 14P of the optical module 14 takesplace, and the slot 22B where mounting and demounting of the protectionwall 14 b takes place. These slots are formed on two stages along theZ-coordinate axis. The slot 22B is formed below and substantiallyparallel to the slot 22A with a partition wall 22PW interposedtherebetween.

The slot 22A is provided with a plurality of slits 22Si (i=1 to n, n isthe positive integer) which are formed at given intervals along theY-coordinate axis in FIG. 7. Each adjacent slits 22Si between them arepartitioned by a partition wall 22Wi (i=1 to n, n is a positiveinteger). The movable contact point portion 26M of one of the contactterminals 26 ai and the corresponding movable contact point portion 28Mof the contact terminal 28 ai are placed in each slit 22Si in such amanner as to face each other.

The slot 22B is provided with a plurality of slits 22Di (i=1 to n, n isthe positive integer) which are formed at given intervals along theY-coordinate axis in FIG. 7. Each adjacent slits 22Di between them areplaced by a partition wall. As shown in FIG. 8, the fixation portion 28Fof one of the contact terminals 28 ai is located in each slit 22Di.Hereby, the fixation terminal portion 28 fa of the contact terminal 28ai protrudes into the slot 22B. Accordingly, this configurationfacilitates inspection and soldering operation at the time ofmaintenance.

Multiple positioning pins 22P to be fitted into positioning holes in theprinted wiring board 16 are formed at a bottom portion of the connectorinsulator. Each positioning pin 22P has a pair of springs 22PS (see FIG.7) configured to press and hold an inner peripheral portion of thecorresponding positioning hole by applying pressure when the positioningpin 22P is fitted into the positioning hole in the printed wiring board16.

In the above-described configuration, in a state where the plugconnector 14P of the optical module 14 is connected to the contactterminals 26 ai and 28 ai inside the slot 22A of the receptacleconnector 22 as shown in FIG. 13A, the protection wall 14 a of theoptical module 14 is biased toward the bottom wall portion 12BP by thetop EMI fingers 12TF. At that time, a given clearance CLD is formedbetween a base end of the plug connector 14P of the optical module 14and an inner peripheral surface of the slot 20PWc in the guide plate20PW of the connector cover 20. In addition, a clearance CLA is formedbetween the protection wall 14 a and the step portion 20R of theconnector cover 20. Moreover, a given clearance larger than theclearance CLD is also formed between the plug connector 14P of theoptical module 14 and an inner peripheral surface of the slot 22A of thereceptacle connector 22. The clearance CLD is set smaller than theclearance CLA.

In the above-described circumstance, when an impact force in thedirection of the Z-coordinate axis in FIG. 7 acts on the transceivermodule assembly 10 and the printed wiring board 16 as shown in FIG. 13Bwhereby a clearance CLB between the protection wall 14 a and the stepportion 20R of the connector cover 20 becomes greater than the clearanceCLA, the base end of the plug connector 14P comes into contact with theinner peripheral surface of the slot 20PWc in the guide plate 20PW ofthe connector cover 20. Accordingly, the plug connector 14P of theoptical module 14 does not collide with the inner peripheral surface ofthe slot 22A of the receptacle connector 22. As a consequence, the plugconnector 14P, the connector terminals 26 ai, and the like are preventedfrom breakage.

As shown in FIG. 16, a heat sink 30 held by the heat sink holder 32 isdetachably attached to an upper surface of the receptacle cage 12.

The heat sink holder 32 has the pair of fixing pieces provided on oneend of the heat sink holder 32 and designed to be detachably fixed withthe pair of hooks 12 ta provided on the upper surface of the receptaclecage 12, and the pair of fixing pieces provided on the other end of theheat sink holder 32 and designed to be detachably fixed with the pair ofhooks 12 tb provided at the receptacle connector-side closed end portionof the receptacle cage 12. Herewith, the heat sink 30 can easily beattached to and detached from the receptacle cage 12 by rotatably movingthe heat sink holder 32 together with the heat sink 30 pivotally aroundthe hooks 12 ta in directions indicated with arrows in FIG. 16.

The heat sink 30 is made of a metal having good thermal conductivitysuch as aluminum or the like. The heat sink 30 has fins 30 fi (i=1 to n,n is a positive integer) which are arranged parallel to one another atgiven intervals in the X-coordinate axis direction.

In the above-described configuration, when the optical module 14 ismounted to the receptacle cage 12, a heat transfer surface (not shown)formed at a lower end of the heat sink 30 comes into direct contact withthe outer peripheral surface of the upper case 14A of the optical module14 via the opening 12 b. Hereby, the heat generated in the opticalmodule 14 is efficiently dissipated through the heat sink 30.

FIG. 17 shows another example of a receptacle cage constituting part ofa transceiver module assembly according to the present invention as wellas a heat sink. Incidentally, the same constituent elements in FIG. 19as those of the example shown in FIG. 7 are assigned the same referencesymbols, and their explanations are omitted.

An optical module receptacle assembly comprises, as main elements, areceptacle cage 42 for detachably accommodating an optical module (notshown) arranged on the above-described printed wiring board 16,receptacle connectors 22′ accommodated in receptacle connectoraccommodating portions of the receptacle cage 42, and a cover 24′ havinga plurality of connector accommodating portions for individuallyaccommodating the receptacle connectors 22′.

The receptacle cage 42 is formed by pressing a thin plate of stainlesssteel or phosphor bronze, or more preferably stainless steel or phosphorbronze having good thermal conductivity. The receptacle cage 42 isprovided with compartments 421 and 422 including module accommodatingportions and the receptacle connector accommodating portions therein.The compartments 421 and 422 are arranged in parallel along a Ycoordinate axis perpendicular to an X-coordinate axis which is anattachment/detachment direction of the optical module in a Cartesiancoordinate system of FIG. 17. Since the compartments 421 and 422 havethe same structure, the compartment 421 is described, and theexplanation of the other compartment 422 is omitted.

The module accommodating portion of the compartment 421 is enclosed andformed by a side wall 426 and a partition wall 427 which are opposite toeach other at a given interval therebetween and their bottom wallportion. The side wall 426 and the partition wall 427 extend along theX-coordinate axis in FIG. 17, that is, the attachment/detachmentdirection of the optical module. The side wall 426 and the partitionwall 427 each have a locking piece 429 placed in the vicinity of amodule slot. Each locking piece 429 is selectively engaged with a fixingpiece of a release plate of the optical module so as to establish thelocked state of the above-described optical module with respect to themodule accommodating portion.

The module accommodating portion has a module slot which is open in theX-coordinate axis direction at one end of the module accommodatingportion. Herewith, the optical module is mounted and demounted throughthe module slot. Tubular front EMI fingers 42FF are provided on theentire periphery of the module slot which has a substantiallyrectangular cross section. Further, front EMI fingers 42FP are providedon the partition wall 427. The front EMI fingers 42FF and the front EMIfingers 42FP form a first shield member. An inner peripheral portion ofthe front EMI fingers 42FF and 42FP comes into contact with an outerperipheral portion of the optical module to be inserted to the fingers42FF and 42FP. In addition, an outer peripheral portion of the front EMIfingers 42FF comes into contact with a peripheral edge of the opening ofthe housing, for example.

Hereby, when the receptacle cage 42 is press-fitted into the opening ofthe housing, a gap between the opening of the housing and the outerperipheral portion of the receptacle cage 42 is shielded by the frontEMI fingers 42FF and 42FP made of a metal. As a consequence, noise isconfined in the housing, and there is no risk of leakage of the noise tothe outside through the gap between the outer peripheral portion of theoptical module and the inner peripheral portion of the moduleaccommodating portion.

In addition, another end of the module accommodating portion opposed tothe module slot communicates with the inside of the receptacle connectoraccommodating portion. An opening that is open along a Z coordinate axisis formed at a portion opposed to the bottom wall portion of thereceptacle cage 42. A heat sink supporting mechanism for detachablysupporting a heat sink 40 which will be described later is provided onthe peripheral edge of the opening.

The structure of each of the heat sinks 40 covering openings of theabove compartments 421 and 422 is made of a metal having good thermalconductivity such as aluminum or the like. The heat sink 40 has aplurality of fins 46Fi (i=1 to n, n is a positive integer) which arearranged parallel to one another at given intervals in the X-coordinateaxis direction. The plurality of fins 46Fi are formed in two rowssubstantially perpendicularly to a flat surface of a base supported bythe heat sink supporting mechanism. A long thin flat path is formed in asubstantially center portion along an arrangement direction of theplurality of fins 46Fi to penetrate the fins 46Fi. A strip-like clip 50a which will be described later is inserted into the flat path. In thismanner, the plurality of fins 46Fi are formed to be away from each otherby a given distance and opposite to each other.

A pair of flanges 46F are formed in each end of the base to be oppositeto each other. As shown in FIG. 19, a raised portion to be inserted intothe opening of the compartment 421 or 422 is formed on a lower endsurface of the heat sink 40.

The heat sink supporting mechanism is individually provided in each heatsink 40. The heat sink supporting mechanism for the compartment 421comprises a top plate forming the peripheral edge of the opening of thecompartment 421 and comprising a top end of the side wall 426, a top endof the partition wall 427, a forward connection portion connecting oneend of the side wall 426 and one end of the compartment wall 427, and abackward connection portion connecting the other end of the side wall426 and the other end of the partition wall 427, hooks 42Fa formed atthree positions of the forward connection portion, and a pair of fixingpieces 24′N of the cover 24′ which protrude outward through holes in aclosed end of the receptacle connector accommodating portion.

The cover 24′ is integrally formed by die-casting a metal material, forexample, and has a profile portion formed by demarcation portions whichare connected to each other and which are respectively inserted into thecompartments 421 and 422 of the receptacle cage 42. The profile portioncomprises a pair of side walls opposite to each other and a top plateconnecting a top end of one side wall and a top end of the other sidewall. A groove corresponding to the partition wall 427 is formed in aboundary portion between the insertion portions in the adjacentcompartments 421 and 422. As shown in FIG. 17, the plurality of fixingpieces 24′N protruding outwardly through the holes of a back plateforming the closed end of the receptacle connector accommodating portionare formed in a back portion of the profile portion of the cover 24′ ata given interval. A pair of nibs 24′M smaller than the fixing pieces24′N are formed at a given interval between the fixing pieces 24′N. Thepair of nibs 24′M are engaged with other holes of the back plate formingthe closed end on the side of the receptacle connector. The connectoraccommodating portions are respectively formed in the demarcationportions to be inserted into the compartments 421 and 422 of the cover24′. The partition wall partitions the adjacent connector accommodatingportions. As shown in FIG. 19, an EMI gasket 54 as a second shieldmember is provided in the periphery of a slot 24′a formed at a front endof the cover 24′. The elastically deformable EMI gasket 54 has, at itscenter, a long hole into which a plug connector 14P of theabove-described optical module is to be inserted. Hereby, the EMI gasket54 shields a gap between an outer peripheral portion of the plugconnector 14P of the optical module and the periphery of the slot 24′,thereby confining noise in the cover 24′. Further, a looped EMI gasket56 as a third shield member is provided in a groove at a lower end ofthe cover 24′. Hereby, the elastically deformable EMI gasket 56 shieldsa gap between lower end surfaces of the cover 24′ and the connector 22′and a mounting surface of a printed wiring board, thus confining noisein the cover 24′.

A long thin clip 50 a of a heat sink holder 50 for detachably fixing theheat sink 40 to the receptacle cage 42 integrally has, at an end 50F, apair of spring pieces 50 f 1 formed at a given interval and three nibs50 f 2 to be fixed to fixing holes of the hooks 42Fa as shown in FIG.18. Further, the clip 50 a integrally has, at the other end 50R, twostopper pieces 50 r 2 with rectangular holes to be fixed to fixingpieces 24′N of the cover 24′ and a pair of sprint pieces 50 r 1 forpressing a flat surface of the heat sink 40. The pair of spring pieces50 r 1 are opposite to the pair of spring pieces 50 f 1 and areintegrally formed at the other end 50R.

In such a structure, in order to attach the heat sink 40 to thereceptacle cage 42, firstly, the raised portion of the heat sink 40 isinserted into an opening of the receptacle cage 42, and the heat sink 40is placed on the top end of the receptacle cage 42.

Next, after the clip 50 a of the heat sink holder 50 is inserted intothe above-described flat path of the heat sink 40, the three nibs 50 f 2and the periphery of the holes of the two stopper pieces 50 r 2 arerespectively engaged with the holes of the hooks 42Fa and the fixingpieces 24′N of the cover 24′. Hereby, the heat sink 40 is pressed to thereceptacle cage 42 and held and locked to the receptacle cage 42. Inthis connection, when the optical module is mounted to the moduleaccommodating portion, an upper plate of the inserted optical module isin sliding contact with the raised portion of the heat sink 40, and theheat sink 40 is raised against the biasing force of the spring pieces 50r 1, and accordingly, the upper plate of the optical module comes inclose contact with the surface of the raised portion of the heat sink40.

Further, in order to unlock and remove the heat sink 40 from thereceptacle cage 42, the periphery of the holes of the stopper pieces 50r 2 is removed and lifted from the fixing pieces 24′N of the cover 24′.

Incidentally, in the example shown in FIG. 19, the EMI gasket 54 as thesecond shield member is provided at the periphery of the slot 24′aformed at a front end of the cover 24′. However, the present inventionis not limited to this example, and for example, it is possible toprovide, in place of the EMI gasket 54, an elastic EMI gasket 58 as thesecond shield member at a proximal end of a plug connector 14′P of anoptical module 14′ as shown in FIG. 20, for example.

As shown in FIG. 20, the optical module 14′ includes the followingconstituents as main elements, namely, an upper case 14′A and a lowerplate 14′B being made of a metal and constituting a profile portion, anda module board (not shown) to be located at a predetermined position ina housing space defined between the upper case 14′A and the lower plate14′B. The module substrate has a similar structure to that of the modulesubstrate 14S shown in FIG. 6B.

A protection wall 14′a of a thin plate shape having a pair of side wallsis formed on one end portion of the upper case 14′A in such a manner asto be continuous with an upper surface of the upper case 14′A and toprotrude in a longitudinal direction.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

What is claimed is:
 1. A receptacle cage used in a receptacle assemblyto be mounted on a wiring board in a housing of a communication system,comprising: a module accommodating portion made of a metal andconfigured to detachably accommodate an optical module, the moduleaccommodating portion having a module slot provided at one end to allowpassage of the optical module, and a bottom wall portion coming incontact with a lower surface of the optical module; a connectoraccommodating portion made of a metal, the connector accommodatingportion communicating with the module accommodating portion and having aconnector cover made of a metal and configured to shield a connector towhich the optical module is connected; a first shield member provided onan entire periphery of the module slot and configured to come intocontact with the optical module and to shield electromagnetic noisegenerated in the module accommodating portion so as to avoid radiationof the noise into the housing; a second shield member provided in aregion corresponding to a boundary portion between the connectoraccommodating portion and the module accommodating portion and at theperiphery of a slot for the connector cover for the connectoraccommodating portion, and configured to come into contact with theoptical module and to shield the electromagnetic noise generated in theconnector accommodating portion; and third shield members provided inregions being different from a region where the second shield member isprovided, and between the connector accommodating portion and the wiringboard, the third shield members configured to shield the electromagneticnoise generated in the connector accommodating portion.
 2. A receptacleassembly to be mounted on a wiring board in a housing of a communicationsystem, comprising: a connector connected to an optical module; areceptacle cage made of a metal and including: a module accommodatingportion made of a metal and configured to detachably accommodate theoptical module, the module accommodating portion having a module slotprovided at one end to allow passage of the optical module, and a bottomwall portion coming in contact with a lower surface of the opticalmodule; a connector accommodating portion made of a metal, the connectoraccommodating portion communicating with the module accommodatingportion and having a connector cover made of a metal and configured toshield a connector to which the optical module is connected; a firstshield member provided on an entire periphery of the module slot andconfigured to come into contact with an outer peripheral surface of theoptical module and to shield electromagnetic noise generated in themodule accommodating portion so as to avoid radiation of the noise intothe housing; a second shield member made of a metal, the second shieldmember provided at the periphery of a slot for the connector cover atthe connector accommodating portion, and configured to come into contactwith the optical module and to shield the electromagnetic noisegenerated in the connector accommodating portion; and third shieldmembers provided in regions being different from a region where thesecond shield member is provided and between the connector accommodatingportion and the wiring board, the third shield members configured toshield the electromagnetic noise generated in the connectoraccommodating portion; wherein a nib formed at the periphery of theconnector cover is engaged with a hole formed at a closed end of theconnector accommodating portion.
 3. A receptacle assembly to be mountedon a wiring board in a housing of a communication system, comprising: aconnector connected to an optical module; a receptacle cage made of ametal and including: a module accommodating portion made of a metal andconfigured to detachably accommodate the optical module, the moduleaccommodating portion having a module slot provided at one end to allowpassage of the optical module, and a bottom wall portion coming incontact with a lower surface of the optical module; a connectoraccommodating portion made of a metal, the connector accommodatingportion communicating with the module accommodating portion and having aconnector cover made of a metal and configured to shield a connector towhich the optical module is connected; a first shield member provided onan entire periphery of the module slot and configured to come intocontact with an outer peripheral surface of the optical module and toshield electromagnetic noise generated in the module accommodatingportion so as to avoid radiation of the noise into the housing; a secondshield member made of a metal, the second shield member provided at theperiphery of a slot for the connector cover at the connectoraccommodating portion, and configured to come into contact with theoptical module and to shield the electromagnetic noise generated in theconnector accommodating portion; and third shield members provided inregions being different from a region where the second shield member isprovided and between the connector accommodating portion and the wiringboard, the third shield members configured to shield the electromagneticnoise generated in the connector accommodating portion; a heat sinkconfigured to dissipate heat generated in the optical module; and a heatsink holder configured to detachably fix the heat sink with respect to aposition right above the module accommodating portion and the connectoraccommodating portion in the receptacle cage, wherein a stopper piece ofthe heat sink holder is fixed to a fixing piece of the connector coverprotruding outside through a hole formed at the receptacle cage.
 4. Atransceiver module assembly to be mounted on a wiring board in a housingof a communication system, comprising: an optical module having a plugconnector; a connector connected to the plug connector of the opticalmodule; and an optical module receptacle assembly including: a moduleaccommodating portion configured to detachably accommodate the opticalmodule, the module accommodating portion having a module slot providedat one end to allow passage of the optical module; a connectoraccommodating portion made of a metal, the connector accommodatingportion communicating with the module accommodating portion andaccommodating the connector; a connector cover provided on the connectoraccommodating portion and configured to cover the connector; a firstshield member made of a metal, the first shield member provided on anentire periphery of the module slot and configured to come into contactwith an outer peripheral surface of the optical module and to shieldelectromagnetic noise generated in the module accommodating portion soas to avoid radiation of the electromagnetic noise into the housing; asecond shield member provided at abase end of the plug connector of theoptical module, and configured to come into contact with the connectorcover and to shield the electromagnetic noise generated in the connectoraccommodating portion; and third shield members provided in regionsbeing different from a region where the first shield member is providedand between the connector accommodating portion and the wiring board,the third shield members configured to shield the electromagnetic noisegenerated in the connector accommodating portion.